Hybrid platform-dependent simulation interface

ABSTRACT

According to one aspect of the present disclosure a system and technique for a hybrid platform-dependent simulation interface is disclosed. The system includes a processor and a simulation engine executable by the processor to provide a simulation environment for an application, the simulation engine simulating a non-simulation environment for hosting the application. The application comprises a library having a platform-independent application programming interface (API) for interacting with the simulation engine and a platform-dependent API providing an interface to the simulation engine using a platform-dependent hardware element, the platform-dependent hardware element unaffecting a non-simulation environment when the application is running in the non-simulation environment.

BACKGROUND

A software application may sometimes be run in a simulation environmentfor verification or other purposes. For example, running a softwareapplication in a simulation environment that simulates a particulartarget operating system/hardware platform that the software applicationis intended to run on enables verification that instructions and/orother program-related operations are performed as intended/expected.

BRIEF SUMMARY

According to one aspect of the present disclosure a method and techniquefor a hybrid platform-dependent simulation interface is disclosed. Themethod includes: encoding an application with a library having aplatform-independent application programming interface (API) forinteracting with a simulation engine, the simulation engine providing asimulated environment for hosting the application; and encoding thelibrary with a platform-dependent API providing an interface to thesimulation engine using a platform-dependent hardware element, theplatform-dependent hardware element unaffecting a non-simulationenvironment when the application is running in the non-simulationenvironment.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

For a more complete understanding of the present application, theobjects and advantages thereof, reference is now made to the followingdescriptions taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is an embodiment of a network of data processing systems in whichthe illustrative embodiments of the present disclosure may beimplemented;

FIG. 2 is an embodiment of a data processing system in which theillustrative embodiments of the present disclosure may be implemented;

FIG. 3 is a diagram illustrating an embodiment of a data processingsystem for a hybrid platform-dependent simulation interface in whichillustrative embodiments of the present disclosure may be implemented;and

FIG. 4 is a flow diagram illustrating an embodiment of a method for ahybrid platform-dependent simulation interface according to the presentdisclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure provide a method and technique fora hybrid platform-dependent simulation interface. For example, in someembodiments, the method and technique includes: encoding an applicationwith a library having a platform-independent application programminginterface (API) for interacting with a simulation engine, the simulationengine providing a simulated environment for hosting the application;and encoding the library with a platform-dependent API providing aninterface to the simulation engine using a platform-dependent hardwareelement, the platform-dependent hardware element unaffecting anon-simulation environment when the application is running in thenon-simulation environment. Embodiments of the present disclosure enableutilization of hardware elements from a target platform/environment forsimulation environment functions such that the selected hardwareelements, if similarly utilized in the non-simulation environment, wouldnot impact or adversely affect the non-simulation platform or runningapplication. For example, embodiments of the present disclosurere-purpose and/or extend hardware elements that would be present in anon-simulation environment for simulation environment functions. Theselected hardware elements may be unused hardware elements or othertypes of hardware elements that if similarly controlled/used in thenon-simulation environment, the application and non-simulation platformwould be unaffected by such use. The simulation library enabling the useof such re-purposed/extended hardware elements for simulation functionsis coded as part of the application itself, thereby resulting in theapplication being executable in simulation or non-simulationenvironments without an indication to the application that it may berunning in a simulation environment. Thus, the simulation library thatis encoded as part of the application effectively hides from theapplication the particular environment (simulation or non-simulation)the application is running in.

As will be appreciated by one skilled in the art, aspects of the presentdisclosure may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present disclosure may take theform of an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present disclosure may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer usable or computer readablemedium(s) may be utilized. The computer readable medium may be acomputer readable signal medium or a computer readable storage medium. Acomputer readable storage medium may be, for example but not limited to,an electronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, or device, or any suitable combinationof the foregoing. More specific examples (a non-exhaustive list) of thecomputer readable storage medium would include the following: anelectrical connection having one or more wires, a portable computerdiskette, a hard disk, a random access memory (RAM), a read-only memory(ROM), an erasable programmable read-only memory (EPROM or Flashmemory), an optical fiber, a portable compact disc read-only memory(CD-ROM), an optical storage device, a magnetic storage device, or anysuitable combination of the foregoing. In the context of this document,a computer readable storage medium may be any tangible medium that cancontain, or store a program for use by or in connection with aninstruction execution system, apparatus or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent disclosure may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present disclosure are described below with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of thedisclosure. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in acomputer-readable medium that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablemedium produce an article of manufacture including instruction meanswhich implement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer orother programmable data processing apparatus to cause a series ofoperational steps to be performed on the computer or other programmableapparatus to produce a computer implemented process such that theinstructions which execute on the computer or other programmableapparatus provide processes for implementing the functions/actsspecified in the flowchart and/or block diagram block or blocks.

With reference now to the Figures and in particular with reference toFIGS. 1-2, exemplary diagrams of data processing environments areprovided in which illustrative embodiments of the present disclosure maybe implemented. It should be appreciated that FIGS. 1-2 are onlyexemplary and are not intended to assert or imply any limitation withregard to the environments in which different embodiments may beimplemented. Many modifications to the depicted environments may bemade.

FIG. 1 is a pictorial representation of a network of data processingsystems in which illustrative embodiments of the present disclosure maybe implemented. Network data processing system 100 is a network ofcomputers in which the illustrative embodiments of the presentdisclosure may be implemented. Network data processing system 100contains network 130, which is the medium used to provide communicationslinks between various devices and computers connected together withinnetwork data processing system 100. Network 130 may include connections,such as wire, wireless communication links, or fiber optic cables.

In some embodiments, server 140 and server 150 connect to network 130along with data store 160. Server 140 and server 150 may be, forexample, IBM System p® servers. In addition, clients 110 and 120 connectto network 130. Clients 110 and 120 may be, for example, personalcomputers or network computers. In the depicted example, server 140provides data and/or services such as, but not limited to, data files,operating system images, and applications to clients 110 and 120.Network data processing system 100 may include additional servers,clients, and other devices.

In the depicted example, network data processing system 100 is theInternet with network 130 representing a worldwide collection ofnetworks and gateways that use the Transmission ControlProtocol/Internet Protocol (TCP/IP) suite of protocols to communicatewith one another. At the heart of the Internet is a backbone ofhigh-speed data communication lines between major nodes or hostcomputers, consisting of thousands of commercial, governmental,educational and other computer systems that route data and messages. Ofcourse, network data processing system 100 also may be implemented as anumber of different types of networks, such as for example, an intranet,a local area network (LAN), or a wide area network (WAN). FIG. 1 isintended as an example, and not as an architectural limitation for thedifferent illustrative embodiments.

FIG. 2 is an embodiment of a data processing system 200 such as, but notlimited to, client 110 and/or server 140 in which an embodiment of asystem for a hybrid platform-dependent simulation interface according tothe present disclosure may be implemented. In this embodiment, dataprocessing system 200 includes a bus or communications fabric 202, whichprovides communications between processor unit 204, memory 206,persistent storage 208, communications unit 210, input/output (I/O) unit212, and display 214.

Processor unit 204 serves to execute instructions for software that maybe loaded into memory 206. Processor unit 204 may be a set of one ormore processors or may be a multi-processor core, depending on theparticular implementation. Further, processor unit 204 may beimplemented using one or more heterogeneous processor systems in which amain processor is present with secondary processors on a single chip. Asanother illustrative example, processor unit 204 may be a symmetricmulti-processor system containing multiple processors of the same type.

In some embodiments, memory 206 may be a random access memory or anyother suitable volatile or non-volatile storage device. Persistentstorage 208 may take various forms depending on the particularimplementation. For example, persistent storage 208 may contain one ormore components or devices. Persistent storage 208 may be a hard drive,a flash memory, a rewritable optical disk, a rewritable magnetic tape,or some combination of the above. The media used by persistent storage208 also may be removable such as, but not limited to, a removable harddrive.

Communications unit 210 provides for communications with other dataprocessing systems or devices. In these examples, communications unit210 is a network interface card. Modems, cable modem and Ethernet cardsare just a few of the currently available types of network interfaceadapters. Communications unit 210 may provide communications through theuse of either or both physical and wireless communications links.

Input/output unit 212 enables input and output of data with otherdevices that may be connected to data processing system 200. In someembodiments, input/output unit 212 may provide a connection for userinput through a keyboard and mouse. Further, input/output unit 212 maysend output to a printer. Display 214 provides a mechanism to displayinformation to a user.

Instructions for the operating system and applications or programs arelocated on persistent storage 208. These instructions may be loaded intomemory 206 for execution by processor unit 204. The processes of thedifferent embodiments may be performed by processor unit 204 usingcomputer implemented instructions, which may be located in a memory,such as memory 206. These instructions are referred to as program code,computer usable program code, or computer readable program code that maybe read and executed by a processor in processor unit 204. The programcode in the different embodiments may be embodied on different physicalor tangible computer readable media, such as memory 206 or persistentstorage 208.

Program code 216 is located in a functional form on computer readablemedia 218 that is selectively removable and may be loaded onto ortransferred to data processing system 200 for execution by processorunit 204. Program code 216 and computer readable media 218 form computerprogram product 220 in these examples. In one example, computer readablemedia 218 may be in a tangible form, such as, for example, an optical ormagnetic disc that is inserted or placed into a drive or other devicethat is part of persistent storage 208 for transfer onto a storagedevice, such as a hard drive that is part of persistent storage 208. Ina tangible form, computer readable media 218 also may take the form of apersistent storage, such as a hard drive, a thumb drive, or a flashmemory that is connected to data processing system 200. The tangibleform of computer readable media 218 is also referred to as computerrecordable storage media. In some instances, computer readable media 218may not be removable.

Alternatively, program code 216 may be transferred to data processingsystem 200 from computer readable media 218 through a communicationslink to communications unit 210 and/or through a connection toinput/output unit 212. The communications link and/or the connection maybe physical or wireless in the illustrative examples.

The different components illustrated for data processing system 200 arenot meant to provide architectural limitations to the manner in whichdifferent embodiments may be implemented. The different illustrativeembodiments may be implemented in a data processing system includingcomponents in addition to or in place of those illustrated for dataprocessing system 200. Other components shown in FIG. 2 can be variedfrom the illustrative examples shown. For example, a storage device indata processing system 200 is any hardware apparatus that may storedata. Memory 206, persistent storage 208, and computer readable media218 are examples of storage devices in a tangible form.

FIG. 3 is an illustrative embodiment of a system 300 for a hybridplatform-dependent simulation interface. System 300 may be implementedon data processing systems or platforms such as, but not limited to,servers 140 and/or 150, clients 110 and/or 120, or at other dataprocessing system locations. In the embodiment illustrated in FIG. 3,system 300 comprises a simulation environment 302 with a simulationengine 310. Simulation environment 302 provided by simulation engine 310is configured to simulate a target software/hardware platform for asoftware application 312. For example, the target software/hardwareplatform (or target non-simulation environment) may include a particulartype of operating system, processor architecture, memory architecture,input/output (I/O) interfaces, bus interfaces, etc., that will hostapplication 312 in a production or non-simulation environment.Simulation engine 310 may comprise software, logic and/or executablecode for performing various functions as described herein (e.g.,residing as software and/or an algorithm running on a processor unit,hardware logic residing in a processor or other type of logic chip,centralized in a single integrated circuit or distributed amongdifferent chips in a data processing system).

Generally, a software application may need to communicate with asoftware simulation environment when the environment is present.However, preferably, the software application would be configured to beunaware of whether the software application is running in a simulationenvironment or non-simulation/native environment. Embodiments of thepresent disclosure provide a simulation interface that is both platformindependent and platform dependent that enables applicationcommunications with the simulation environment when present while alsohiding from the application the environment in which the application iscurrently running.

In the embodiment illustrated in FIG. 3, application 312 is encodedand/or written to include one or more production and/or applicationlibraries 320 and one or more simulation libraries 322. Libraries 320and 322 may comprise software, logic and/or executable code forperforming various functions as described herein (e.g., residing assoftware and/or an algorithm running on a processor unit, hardware logicresiding in a processor or other type of logic chip, centralized in asingle integrated circuit or distributed among different chips in a dataprocessing system). In FIG. 3, simulation environment 302 includes avariety of types of simulated hardware components such as a memorymapped I/O interface 330, a central processing unit 332, an I/Ointerface 334, and two digital I/Os 340 and 342. However, it should beunderstood that simulation environment 302 may be configured to simulateadditional and/or different types of software and/or hardware elementsassociated with a target non-simulation environment.

Libraries 320 are used by application 312 to affect a state change in,for example, digital I/O 340. Digital I/O 340 represents/simulates areal or native hardware element of a non-simulation environment forhosting application 312. For example, application 312 may make a call toan API in library 320 that invokes a device driver that performs thenecessary operations (e.g., writes to MMIO 330) to change the state ofdigital I/O 340. In a non-simulation environment, digital I/O 340 maycomprise a pin that is connected to a general purpose I/O device 350 orother hardware element such that digital I/O 340 is in use in the nativeor non-simulation environment.

Embodiments of the present disclosure re-purpose and/or extend thefunctions of existing hardware elements that would be found in thenon-simulation environment to interface with simulation engine 310 inthe simulation environment 302. For example, in FIG. 3, consider thatdigital I/O 342 would be unused in a non-simulation environment (e.g.,connected to ground, no connection, etc.). In simulation environment302, interface logic 360 may interface with digital I/O 342 insimulation environment 302 to use a change in state or data transferassociated with digital I/O 342 to interface with simulation engine 310to indicate a command or other type of signal. Digital I/O 342 may alsobe used to input a condition/command to application 312 by simulationengine 310. Thus, in this context, the function of digital I/O 342 in anon-simulation environment would be that of non-use which is re-purposedto have a simulation-related function when application 312 is running insimulation environment 302. Accordingly, a select hardware element thatwould be found in the non-simulation environment is used in thesimulation environment 302 for interfacing with simulation engine 310such that use of the select hardware element in the non-simulationenvironment would not affect (or negligibly affect) the non-simulationplatform or running application when running in the non-simulationenvironment.

In FIG. 3, simulation library 322 includes platform-independent APIs 370and platform-dependent APIs 372. Platform-independent APIs 370 compriseprogramming interfaces that are configured to be independent of thenon-simulation environment hosting application 312 such that the APIs370 may be used with a variety of types of operating systems running ona variety of different hardware platforms. Platform-dependent APIs 372are configured, designed and/or built for a particular target or nativenon-simulation environment that will be hosting application 312. Forexample, for a particular operating system/hardware non-simulationplatform/environment, particular I/O pins, memory regions (e.g., regionsof memory 206), signal buses (e.g., bus 202), etc., may be unused orwould otherwise have no effect on such platform in response to callsfrom library 322 (e.g., digital I/O 342 attached to ground in thenon-simulation platform). Thus, library 322 provides a simulatorcommunication facility when running in simulation environment 302 butwill not affect the state of application 312 or the non-simulationplatform hosting application 312 when application 312 is not running insimulation environment 302. Library 322 APIs 372 are tailored to theparticular target, non-simulation software/hardware platform application312 will be running on such that select hardware elements may bere-purposed and/or extended for use in simulation environment 302. Thesimulation functionality provided by using unused or other benignnon-simulation platform hardware elements may include, but not belimited to, real time logging control for select simulation objects,simulation environment 302 control (e.g., simulator fidelity levelcontrol, error injection control, performance mode control, etc.), trapon events, conditions or instructions, etc.

Thus, embodiments of the present disclosure utilize non-simulationenvironment hardware elements to provide simulation functionality wherethe use of such non-simulation environment hardware elements leaveapplication 312 and the hosting non-simulation platform unaffected whennot running in the simulation environment 302. In some embodiments,hardware elements in the non-simulation environment may be extended toprovide additional simulator functionality. For example, in someembodiments, an address range on a processor local bus present in thenon-simulation environment may be extended in simulation environment 302to provide additional simulator functionality. Additionally, “ghost”peripheral devices may be added in simulation environment 302 to I/Obuses present in the non-simulation environment (e.g., an I²C peripheraldevice) where such peripheral devices may be used for additionalsimulation actions. Thus, library 322 is encoded, included and/orotherwise forms part of application 312 that would run in anon-simulation environment such that library 322 does not adverselyaffect non-simulation use of the application 312 or the non-simulationplatform running the application 312.

FIG. 4 is a flow diagram illustrating an embodiment of a method for ahybrid platform-dependent simulation interface. The method begins atblock 402, where platform-independent API(s) 370 are created/generated.At block 404, a target non-simulation environment/platform is identifiedfor application 312 (e.g., a particular operating system/hardwareenvironment that will host application 312 in a production ornon-simulation environment). At block 406, one or more hardware elementsof the target non-simulation environment/platform are identified thatmay be re-purposed/extended for simulation environment functionality(e.g., grounded and/or unused I/O connections, unused memory registers,bus addresses, etc.). At block 408, platform-dependent API(s) 372 arecreated/generated based on the hardware elements identified at block406.

At block 410, platform-independent API(s) 370 and platform-dependentAPI(s) 372 are encoded into and/or otherwise generated as part ofapplication 312 (e.g., as simulation library 322). At block 412,application 312 may be launched in simulation environment 302. At block414, library 322 receives a call (e.g., from simulation engine 310). Atblock 416, library 322 causes a state change or other signal process toa particular hardware element re-purposed/extended from thenon-simulation environment for simulation environment functionality.

Thus, embodiments of the present disclosure enable utilization ofhardware elements from a target platform/environment for simulationenvironment functions such that the selected hardware elements, ifsimilarly utilized in the non-simulation environment, would notadversely affect the non-simulation platform or running application. Forexample, embodiments of the present disclosure re-purpose and/or extendhardware elements that would be present in a non-simulation environmentfor simulation environment functions. The selected hardware elements maybe unused hardware elements or other types of hardware elements that ifsimilarly controlled/used in the non-simulation environment, theapplication and non-simulation platform would be unaffected by such use.The simulation library enabling the use of such re-purposed/extendedhardware elements for simulation functions is coded as part of theapplication itself, thereby resulting in the application beingexecutable in simulation or non-simulation environments without anindication to the application that it may be running in a simulationenvironment. Thus, the simulation library that is encoded as part of theapplication effectively hides from the application that particularenvironment (simulation or non-simulation) the application is runningin.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosure has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the disclosure in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the disclosure. Theembodiment was chosen and described in order to best explain theprinciples of the disclosure and the practical application, and toenable others of ordinary skill in the art to understand the disclosurefor various embodiments with various modifications as are suited to theparticular use contemplated.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

1-6. (canceled)
 7. A system, comprising: a processor; and a simulationengine executable by the processor to provide a simulation environmentfor an application, the simulation engine simulating a non-simulationenvironment for hosting the application; and wherein the applicationcomprises a library having a platform-independent applicationprogramming interface (API) for interacting with the simulation engineand a platform-dependent API providing an interface to the simulationengine using a platform-dependent hardware element, theplatform-dependent hardware element unaffecting a non-simulationenvironment when the application is running in the non-simulationenvironment.
 8. The system of claim 7, wherein the platform-dependentlibrary comprises code for utilizing an unused input/output (I/O)interface of the non-simulation environment to interface with thesimulation engine.
 9. The system of claim 7, wherein theplatform-dependent library comprises code for utilizing an unused memoryregion of the non-simulation environment to interface with thesimulation engine.
 10. The system of claim 7, wherein theplatform-dependent library comprises code for utilizing an unused signalbus of the non-simulation environment to interface with the simulationengine.
 11. The system of claim 7, wherein the platform-dependentlibrary comprises code for utilizing an address range on a bus that isnonexistent in the non-simulation environment to interface with thesimulation engine.
 12. The system of claim 7, wherein theplatform-dependent library comprises code to communicate over an I/O busof the non-simulation environment to a peripheral device that isnonexistent in the non-simulation environment.
 13. A computer programproduct for a hybrid platform-dependent simulation interface, thecomputer program product comprising: a computer readable storage mediumhaving computer readable program code embodied therewith, the computerreadable program code comprising computer readable program codeconfigured to: receive a call to a library having a platform-independentapplication programming interface (API) for interacting with asimulation engine, the simulation engine providing a simulationenvironment for an application simulating a non-simulation environmentfor hosting the application; and interface by a platform-dependent APIwith the simulation engine using a platform-dependent hardware element,the platform-dependent hardware element unaffecting a non-simulationenvironment when the application is running in the non-simulationenvironment.
 14. The computer program product of claim 13, wherein thecomputer readable program code is configured to utilize an unusedinput/output (I/O) interface of the non-simulation environment tointerface with the simulation engine.
 15. The computer program productof claim 13, wherein the computer readable program code is configured toutilize an unused memory region of the non-simulation environment tointerface with the simulation engine.
 16. The computer program productof claim 13, wherein the computer readable program code is configured toutilize an unused signal bus of the non-simulation environment tointerface with the simulation engine.
 17. The computer program productof claim 13, wherein the computer readable program code is configured toutilize an address range on a bus that is nonexistent in thenon-simulation environment to interface with the simulation engine. 18.The computer program product of claim 13, wherein the computer readableprogram code is configured to communicate over an I/O bus of thenon-simulation environment to a peripheral device that is nonexistent inthe non-simulation environment. 19-24. (canceled)